If you are unable to generate IRN For E-Invoice, you can check the following Errors:
Step 1: Sales voucher numbers cannot start with zero and voucher numbers cannot exceed 16 characters.
Step 2: Validate GSP ID. To do this, go to Administration, Configurations, then Features & Options, and finally, GST/VAT.
Step 3: Then Click on GSP configurations and Validate.
Step 4: Verify that the location, pincode, and address in the party master are correctly mentioned.
Step 5: Ensure that the GSTIN number is correct and validated.